Contact us
We read every message. Whether you have a question, a feature idea or a correction, get in touch by email.
This is a small independent project, so replies can take a few days.
What to write to us about
- Data corrections: a value, discovery credit or name origin that looks wrong.
- Bugs: something broken or confusing on a page, tool or printable file.
- Feature ideas: new properties, tools or pages you would find useful.
- Permissions: using our printable files or content beyond personal and classroom use.
- Copyright or privacy concerns: see our Terms and Privacy Policy.
Reporting a data correction
Please include the element or page, the value you believe is wrong, and a reference (a handbook, paper or database link). Values differ between sources, so a citation helps us review it quickly. Our sources are listed on the About page.
Reporting a bug
Tell us the page address, what you expected and what happened, plus your device, browser and screen size if it is a layout problem. A screenshot helps.
Before you write
We can’t help with homework answers or lab-safety advice. For how search queries work, see the search guide.